JP3417331B2 - Cylinder head and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a water jacket of a cylinder head and a manufacturing method thereof.

[0002]

2. Description of the Related Art A cylinder head is a member that constitutes an engine together with a cylinder block, and the recessed portion on the lower surface thereof constitutes the ceiling of the combustion chamber of the engine. An intake valve for supplying combustion gas to the combustion chamber, an exhaust valve for exhausting the combustion chamber, an operating mechanism for these valves, and an ignition plug are attached to the cylinder head at predetermined positions. Then, on the combustion chamber of the cylinder head, as shown in Japanese Utility Model Laid-Open No. 1-130048, a water for collectively cooling the periphery of the combustion chamber, a support portion of the valve, a plug hole for an ignition plug, and the like. A jacket is formed in the longitudinal direction of the cylinder head.

[0003]

Generally, since the cooling effect around the combustion chamber directly affects the performance of the engine, there is a demand for sufficiently flowing cooling water in the vicinity of the combustion chamber. . On the other hand, the support portion of the valve is not required to be cooled as strongly as around the combustion chamber. However, in the cylinder head, the same water jacket is used for both cooling the surroundings of the combustion chamber and cooling the other parts, so that the cooling water is allowed to flow in an amount corresponding to the requirements of the vicinity of the combustion chamber and other parts. I can't. For example, even if the cooling water flowing to the water jacket is increased in order to improve the cooling effect around the combustion chamber, the cooling water also flows near the support part of the valve, etc. There is a problem that it cannot be improved.

The present invention promotes cooling around the combustion chamber by allowing the cooling water to flow separately into the vicinity of the combustion chamber and other portions, facilitates the production of the water jacket, and increases the strength around the plug hole. The purpose is to improve the cooling efficiency.

[0005]

The above-mentioned problems can be solved by the inventions of the respective claims. The invention according to claim 1 is a cylinder head in which a water jacket is partitioned by a wall formed along a flow direction of cooling water into a portion for cooling around a combustion chamber and a portion for cooling other portions. The plug hole communicating with the combustion chamber is formed by casting a tube, and the tube is arranged so as to pass through a water jacket that cools around the combustion chamber and a water jacket that cools other parts.
The wall thickness of the tube is the thickness of the
Thickness is the thickness of the part that penetrates the water jacket
It is characterized by being set smaller than the size .

According to the present invention, since the water jacket is divided into a portion for cooling the periphery of the combustion chamber and a portion for cooling the other portions, it is possible to separately flow the cooling water in the vicinity of the combustion chamber and other portions. become. Therefore, it becomes possible to flow the required amount of cooling water in the vicinity of the combustion chamber, and it is possible to promote cooling around the combustion chamber. Furthermore, since the plug hole is formed by casting and enclosing the tube, the tube that is the material of the plug hole can be manufactured by various methods before casting, for example, by forging. Therefore, it is possible to easily improve the strength around the plug hole as compared with the conventional case where the plug hole is formed by casting. Further, the wall thickness can be reduced while ensuring the strength around the plug hole. Therefore, the temperature in the plug hole can be efficiently transmitted to the cooling water in the water jacket, and the cooling efficiency in the plug hole is improved. Also of the tube
As for the wall thickness, the thickness of the part to be cast is
It is set smaller than the wall thickness of the part that penetrates the
Therefore, the temperature of the cast-in part of the tube rises.
It becomes easier and the weldability between the tube and the molten metal is improved.

[0007]

[0008]

The cylinder head manufacturing method according to a second aspect of the present invention includes a step of manufacturing a tube for forming a plug hole communicating with the combustion chamber and a step of forming the tube into a core type.
And blow sand into the core so that the tube
Forming the first core for the water jacket
Process for integrating the first core and the tube
With the tip of the tube threaded,
A wobbled hole that has a receiving hole
Forming a second core for a data jacket, and
Connect the tip of the tube integrated with the first core to the second core.
Pass through the receiving hole and fit the step of the tube with the receiving hole
In this state, the tip end surface of the tube is brought into contact with a mold for molding a combustion chamber, and a casting pin is inserted into the tube from the first core side to hold the tube.
It is characterized in that it has a step of performing mold clamping and casting .

According to the present invention, the tube and the first core are integrated, and the tip of the tube is fitted into the receiving hole of the second core. Positioning of the core becomes easy. Furthermore, since the tube is pressed by the combustion chamber molding die and the casting pin in a state where the first core is positioned with respect to the second core, the first core with respect to the second core during pouring. The core will not be displaced. Therefore, it becomes easy to make a two-stage water jacket, which has been difficult to make due to the problem of positioning the core. That is, the cylinder head according to claim 1 can be manufactured by the present invention.

According to a third aspect of the present invention, there is provided a method of manufacturing a cylinder head, wherein a lower portion of a tube constituting a ceiling portion of a combustion chamber to a lower portion of a plug hole, and a main portion of the plug hole having a structure capable of being fitted to the lower portion of the tube. And a step of manufacturing the tube upper part that constitutes the above, and a state in which the tube upper part is integrated with the first core for the water jacket being penetrated and the tube lower part is penetrated with the second core for the water jacket. a step of integrating in, said tube top and fitted with a tube bottom, after setting the first core and the second core in the mold, characterized in that a step of performing a casting.

According to the present invention, the lower part of the tube is cast from the ceiling of the combustion chamber to the lower part of the plug hole, and the main part of the plug hole is cast from the upper part of the tube. Therefore, the lower tube portion and the upper tube portion, which are materials for the ceiling portion of the combustion chamber and the plug hole, can be manufactured by various methods such as forging before casting. Therefore, the strength from the ceiling of the combustion chamber to the plug hole can be more easily improved than in the conventional case where the ceiling of the combustion chamber and the plug hole are formed by casting. Furthermore, the wall thickness can be reduced while ensuring the strength from the ceiling of the combustion chamber to the plug hole. Therefore, the cooling effect in the combustion chamber and the plug hole can be improved. Since the tube upper part and the tube lower part are fitted together, the positioning of the first core and the second core becomes easy.

A cylinder head manufacturing method according to a fourth aspect of the present invention is the cylinder head manufacturing method according to the third aspect, wherein a lower portion of the tube is integrated with a second core for a water jacket. after the step, characterized by having a step of applying a coating agent to the edge of the portion constituting the ceiling of the combustion chamber in the tube bottom.

According to the present invention, the mold coating agent is applied to the edge of the lower portion of the tube to be cast-in, so that the mold coating agent can be removed between the casting base material and the edge of the lower portion of the tube after casting. To form a gap. Therefore, the thermal expansion of the lower portion of the tube can be absorbed by the gap, and the thermal strain of each cylinder does not affect the adjacent cylinders.

The method of manufacturing a cylinder head according to a fifth aspect is the method of manufacturing a cylinder head according to any one of the second to fourth aspects, wherein the step of cooling the tube during casting is performed. It is characterized by having .

For this reason, the solidification of the molten metal in the vicinity of the tube is promoted, the structure of the metal becomes finer, and the strength around the plug hole can be increased. Further, it becomes possible to shorten the time from the start of casting to the release.

A cylinder head manufacturing method according to a sixth aspect of the present invention is the cylinder head manufacturing method according to any one of the second to fifth aspects, wherein the fins are provided at the portions that come into direct contact with the molten metal. Fabricate the formed tube
It is characterized by having a step of Therefore, the function of the fins increases the contact area between the tube and the molten metal and improves the weldability. A method of manufacturing a cylinder head according to claim 7 is described in any one of claims 2 to 6.
And method for manufacturing a cylinder head, the portion being cast-in
The wall thickness of the part that penetrates the water jacket
A process to manufacture a tube that is set smaller than the dimensions.
It is characterized by having a degree. Because of this, tube casting
The temperature of the wrapped part easily rises, and the tube and molten metal
The weldability with is improved.

[0018]

DETAILED DESCRIPTION OF THE INVENTION (First Embodiment) FIG.
The cylinder head and the method for manufacturing the cylinder head according to the first embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1A is a cross-sectional view of the cylinder head in the width direction.
FIG. 2B is a bottom view of the cylinder head, and FIG. 2 is a vertical cross-sectional view of a mold for manufacturing the cylinder head. 3 to 5 are views of a core for forming a water jacket of the cylinder head.

The cylinder head 1 is a cylinder head made of an aluminum alloy used in a four-cylinder engine and is formed by casting. The lower surface 1d of the cylinder head 1 is provided with dents at four positions in the longitudinal direction,
The dents form the ceiling portion 2t of the combustion chamber 2 of the engine. It should be noted that FIG. 1B shows a ceiling portion 2t of one combustion chamber 2. Further, from the side surface of the cylinder head 1 to the combustion chamber 2, there are two intake passages 3 per cylinder.
And two exhaust passages 4 are formed, and an intake port 3s which is an opening portion of the intake passage 3 and an exhaust port 4h which is an opening portion of the exhaust passage 4 are formed in the ceiling portion 2t of the combustion chamber 2. (See FIG. 1B). An intake valve (not shown) for opening and closing the intake passage 3 is attached to the position of the intake port 2s, and an exhaust valve (opening and closing) for opening and closing the exhaust passage 4 at the position of the exhaust port 4h. Is not installed).

An opening 5p of a plug hole 5 for attaching an ignition plug (not shown) is provided at the center of the ceiling portion 2t of the combustion chamber 2. The plug hole 5 is formed so as to vertically penetrate the cylinder head 1 (see FIG. 1A), and the combustion chamber side of the plug hole 5 is formed by casting and enclosing a tapered tube 15. . The tube 15 is a forged product, and is manufactured as thin as possible while ensuring a predetermined strength. A step 15d having a conical convex shape is formed on the outer circumference of the tip of the tube 15.
Is formed, and a female screw for a spark plug is formed on the inner peripheral surface on the tip side (lower side) of the step 15d. Also, behind the step 15d of the tube 15 (upper side)
Is shaped to accommodate the spark plug.

Further, in the longitudinal direction of the cylinder head 1, a lower water jacket 6 for flowing cooling water is formed along the ceiling portion 2t of each combustion chamber 2. Then, the heat of the wall of each combustion chamber 2 is absorbed by the cooling water flowing through the lower water jacket 6. Further, the lower water jacket 6 is attached to the tube 1
It is formed so as to surround 5 and the heat transmitted from the combustion chamber 2 to the tube 15 is also absorbed by the cooling water of the lower water jacket 6.

Immediately above the lower water jacket 6, an upper water jacket 7 for flowing cooling water around the stem guide which is a support portion of the intake valve and the exhaust valve and other portions is thin with the lower water jacket 6. It is formed in a state of being vertically stacked via the wall 1w. Therefore, the upper water jacket 7
The heat transmitted from the combustion chamber 2 to the stem guide via the valve and the heat of other portions are absorbed by the cooling water flowing through the valve. Furthermore, since the upper water jacket 7 is formed so as to surround the tube 15, the combustion chamber 2
The heat transmitted from the tube 15 to the tube 15 is also absorbed by the cooling water of the upper water jacket 7. An oil jacket 8 for flowing oil is formed on the water jacket 7.

As described above, according to the cylinder head 1, the water jackets 6 and 7 are divided into a portion for cooling the periphery of the combustion chamber by the wall 1w formed along the flow direction of the cooling water and a portion for cooling the other portions. Because they are divided,
The cooling water can be separately flowed into the vicinity of the combustion chamber 2 and other portions. Therefore, it becomes possible to flow a required amount of cooling water in the vicinity of the combustion chamber 2, and it is possible to promote cooling around the combustion chamber. Therefore, for example, it is possible to increase the compression ratio of the engine and improve the output of the engine. It is also possible to reduce the cooling water flow rate outside the combustion chamber and increase the cooling water flow rate around the combustion chamber by that amount, and to improve the cooling efficiency around the combustion chamber without increasing the total cooling water flow rate. Can be improved. Furthermore, the upper and lower water jackets 6 and 7 are walls 1w
Since it is partitioned by, its water jacket 6,7
The rigidity of the cylinder head 1 is improved by the amount of the wall 1w as compared with the case of integrally molding.

The plug hole 5 has a tube 15
Since it is formed by casting, the strength around the plug hole can be improved more easily than when the plug hole 5 is formed only by casting. Therefore, it is possible to reduce the wall thickness between the plug hole 5 and the water jackets 6 and 7 while ensuring the strength around the plug hole. Therefore, the temperature in the plug hole can be efficiently transmitted to the cooling water in the water jacket, and the cooling effect in the plug hole can be improved.

Next, referring to FIG. 2, the cylinder head 1 will be described.
The structure of the mold 20 for manufacturing is explained. here,
FIG. 2 shows a vertical cross-sectional view of the mold 20 corresponding to the cross-sectional view of the cylinder head 1 of FIG. The mold 20
The following description will be made assuming that the width direction is the X-axis direction, the longitudinal direction (the direction perpendicular to the paper surface) is the Y-axis direction, and the height direction is the Z-axis direction. The mold 20 is composed of an upper mold 22, a lower mold 24, and a slide mold 26. The upper mold 22 is a mold for molding the upper surface 1u of the cylinder head 1, and is connected to an elevating device (not shown) so that it can be moved up and down with respect to the lower mold 24.

A molding surface 22f for molding the upper surface 1u of the cylinder head 1 is provided in the central portion of the upper mold 22 so as to be long in the Y-axis direction, and four casting holes are formed in the center of the molding surface 22f. The pins 22n are attached at equal intervals in the Y-axis direction. The die-cast pin 22n is inserted into the tube 15 for forming a plug hole when the die is clamped.
5 is a pin for pressing the plug 5 from above and for molding the plug hole 5 at the time of casting, and is tapered so as to be tapered.

The slide mold 26 is the cylinder head 1.
Is a mold for molding the front, rear, left, and right side surfaces 1s, and is composed of a plurality of molds. Each die of the slide die 26 is connected to a slide device (not shown) so that it can slide laterally on the lower die 24.
It should be noted that a plurality of molds forming the slide mold 26 will be collectively referred to as a slide mold 26 for the following description. A molding surface 26f for molding the side surface 1s of the cylinder head 1 is formed on the side surface of the slide mold 26, and a sand core 26e (intake air) that forms the intake passage 3 at a predetermined position of the molding surface 26f. A passage core 26e) and a sand core 26x (exhaust passage core 26x) forming the exhaust passage 4 are attached.

The lower mold 24 is a mold for molding the lower surface 1d of the cylinder head 1, and a molding surface 24f is formed in the central portion of the lower mold 24 to be long in the Y-axis direction. A core metal mold 24c for molding the combustion chamber 2 of the cylinder head 1 is fixed at a position facing the casting pin 22n of the upper mold 22 at the center position of the molding surface 24f. In FIG. 2, the tip portions of the intake passage core 26e and the exhaust passage core 26x are omitted in accordance with FIG. Child 26e
And the tip of the exhaust path core 26x is the core mold 24 for the combustion chamber.
It comes to fit with c.

Inside the mold 20, a first core 28 for forming the upper water jacket 7 of the cylinder head 1 and a second core 29 for forming the lower water jacket 6 are also provided. Is positioned. The first core 28 is a sand core and is integrated with the four tubes 15 forming the plug holes 5, as shown in FIGS. 3 to 5. In order to mold the first core 28, first, the four tubes 15 which have been molded by forging in advance are set at predetermined positions of a core mold (not shown). Next, the shell sand is blown into the core mold and the shell sand is solidified, so that the tube 15 is penetrated through the first core 28 to integrate the two. Here, in order to prevent rotation of the tube 15 with respect to the first core 28, it is preferable to form a groove or the like on the surface of the tube 15.

The second core 29 is also a sand core,
A receiving hole 29r is formed at a position corresponding to each tube 15 of the first core 28. The receiving hole 29r is provided with an opening through which the tip of the tube 15 can be passed, and a ring-shaped receiving portion which can fit with the step 15d of the tube 15 is formed around the opening. While the step 15d of each tube 15 is fitted in the receiving hole 29r of the second core 29, the first core 28 is held in a fixed positional relationship with respect to the second core 29. The tip portion of each tube 15 projects below the second core 29 by a predetermined size (see FIG. 5).

The second core 29 is formed by a foot-shaped skirting board (not shown) and skirting boards provided on both sides in the longitudinal direction of the mold 2.
It is positioned at a predetermined position of 0. On the other hand, the first core 28
As described above, the upper mold 2 is attached to each tube 15 while being held in a fixed positional relationship with the second core 29.
The second casting pin 22n is inserted and pressed by the casting pin 22n from above.
It is possible to prevent the floating of the sheet (see FIG. 2). Further, a third core 30 for forming the oil jacket 8 is positioned above the first core 28 inside the mold 20. It should be noted that the third core 30 is also formed by a skirting board (not shown) provided on both sides in the longitudinal direction of the mold 20.
Is positioned at a predetermined position.

Next, a method of manufacturing the cylinder head 1 using the mold 20 will be described. First, the steps 15d of the four tubes 15 of the first core 28 are shown in FIGS.
As shown in FIG. 5, the first core 28 and the second core 29 are combined by fitting them into the receiving holes 29r of the second core 29. Next, with the first core 28 and the second core 29 combined, the second core 29 is set at a predetermined position of the mold 24. Further, the intake passage core 26e and the exhaust passage core 2
6x and the third core 30 for the oil jacket to the mold 24
Set to.

In this way, the cores 28, 29, 30,
The mold 20 is clamped with the molds 26e and 26x set. When the mold clamping of the mold 20 is performed, FIG.
As shown in, the tip end surface of each tube 15 of the first core 28 is fitted with the core mold 24c for the combustion chamber, and
Casting pins 22n are inserted into the tube 15 from above and are pressed by the casting pins 22n. Further, as described above, the tips of the intake passage core 26e and the exhaust passage core 26x are fitted to the core metal mold 24c for the combustion chamber.

When the mold clamping is completed in this way, the molten metal is poured into the mold 20. As shown in FIG. 1 (A), the poured molten metal casts the upper end portion and the lower end portion of the tube 15 and the middle portion of the tube 15 which is not covered by the first core 28 and the second core 29. And solidify. Then, after a lapse of a predetermined time, when the molten metal is solidified, the mold is opened and the cast product is taken out. The sand core is removed from the cast product taken out from the mold 20 in a later step, deburring and the like are performed, and the cylinder head 1 is completed.

As described above, in the method of manufacturing the cylinder head 1 according to this embodiment, the tube 15 and the first core 28 are used.
Is integrated and the tip portion of the tube 15 is fitted into the receiving hole 29r of the second core 29.
The positioning of the first core 28 with respect to the core 29 becomes easy. Furthermore, since the tube 15 is pressed by the core mold 24c for molding the combustion chamber and the casting pin 22n while the first core 28 is positioned with respect to the second core 29, the first core 28 is positioned at the time of pouring. First core 28 to second core 29
Does not rise and become misaligned. Therefore, it becomes easy to make a two-stage water jacket, which has been difficult to make due to the problem of positioning the core.

In this embodiment, the first core 28 and the second core 29 are set in the mold 20 in a combined state, but the first core 28 is set in the process of clamping the mold 20. Two
8 and the second core 29 may be combined.

(Second Embodiment) A method of manufacturing a cylinder head according to a second embodiment of the present invention will be described below with reference to FIGS. 6 and 7. Here, FIG. 6 and FIG. 7 are vertical cross-sectional views of the mold 50 and the mold 60 used when the method of manufacturing the cylinder head according to the present embodiment is carried out. The mold 20 described in the first embodiment is used.
The same members as those of No. 1 are given the same numbers and their explanations are omitted.

Inside the upper mold 22 constituting the mold 50, a main pipe 5 for cooling water is provided in the central longitudinal direction (Y-axis direction) thereof.
2k is formed, and a cooling pipe 52t branched from the main pipe 52k is formed in the internal axial direction of the cast pin 52n. The cooling pipe 52t is open at the tip surface of the casting pin 22n. Also, the lower mold 24
A drain pipe 54k for discharging the cooling water supplied into the tube 15 from the cooling pipe 52t of the casting pin 52n is formed in the center of the core mold 54c attached to the.

Next, a method of manufacturing the cylinder head 1 using the mold 50 will be described. First, as described in the first embodiment, the first core 2 is placed inside the mold 50.
When the second core 29 and the like are set, the die 50 is clamped. Then, after the mold is clamped, the molten metal is injected into the mold 50, and is cooled from the main pipe 52k of the upper mold 22 to the cooling pipe 52t of the casting pin 52n and the drain pipe 54k of the core mold 54c via the tube 15. The water is washed away.
Thereby, the tube 15 is cooled, the solidification of the molten metal around the tube 15 is promoted, the structure of the aluminum alloy is refined, and the strength around the tube 15 is improved. Furthermore, it is possible to shorten the time from the start of casting to the release.

In this way, when the molten metal is solidified for a predetermined time after pouring the molten metal, the mold is opened and the cast product is taken out. FIG. 7 shows a mold 60 of another type used when the method of manufacturing the cylinder head according to the present embodiment is carried out. The mold 60 includes a cooling water feed pipe 62a and a return pipe 62 inside a casting pin 62n.
The tube 15 is indirectly cooled by forming b and cooling the cast pin 62n. As a result, the cooling efficiency for the tube 15 is slightly lowered, but leakage of cooling water or the like can be reliably prevented. In the method of manufacturing the cylinder head according to the present embodiment, the cooling water is used for cooling the tube 15, but it is also possible to cool it with air or the like.

(Third Embodiment) A method of manufacturing a cylinder head according to a third embodiment of the present invention will be described below with reference to FIG. FIG. 8 is a vertical cross-sectional view of a tube 75 for molding the plug hole 5 used in the method of manufacturing the cylinder head according to this embodiment. The tube 75 has a thick portion 75t (intermediate portion 75t) that is integrated with the first core 28, and has a distal end portion 75e (lower end portion) and a proximal end portion 75w ( And the upper end) are formed to be thin. As a result, the tube 75 is integrated with the first core 28 in the middle part 75.
At t, the strength can be secured, and the temperature easily rises at the tip end portion 75e and the base end portion 75w that are cast in the molten metal, and the weldability with the molten metal improves. Also, the tube 75
A ring-shaped fin 75 is formed on the outer peripheral surface of the base end portion 75w of the
Since f is formed, the fin 75f further improves the weldability with the molten metal.

Further, the tip outer peripheral surface 75 of the tube 75
r is chamfered in an arcuate cross section, and its chamfer depth is set to be deeper than the depth of the valve seat surface of the intake port 3s and the exhaust port 4h (see FIG. 1B). Therefore, when the valve seat surface is cut after casting, the blade of the cutter does not come into contact with the tip of the tube 75, and the occurrence of burrs and the like is suppressed.

(Fourth Embodiment) Hereinafter, FIG. 9 and FIG.
0 and FIG. 11, a cylinder head manufacturing method according to a fourth embodiment of the present invention will be described. FIG. 9 is a cross-sectional view in the width direction of the cylinder head according to the present embodiment, FIG.
FIG. 11 shows a vertical cross section of a core and a tube used in the method of manufacturing a cylinder head according to the present embodiment.
In the cylinder head 80 according to the present embodiment, a tube 95 that forms the combustion chamber side of the plug hole 85 is vertically divided into two parts, and a tube lower portion 95d that forms the lower side of the tube 95 simultaneously forms the combustion chamber 82. The ceiling portion 82t can be configured. The cylinder head 80
The other structure is the same as that of the cylinder head 1 according to the first to third embodiments.

The tube lower portion 95d is composed of a substantially cylindrical portion and a flange-shaped lower end portion, and the flange-shaped lower end portion is a ceiling portion 82t of the combustion chamber 82.
Make up. Further, a fitting concave portion 95 of a tube upper portion 95u, which will be described later, is provided on the upper portion of the substantially cylindrical portion of the tube lower portion 95d.
A fitting convex portion 95p inserted into m is formed coaxially. The tube upper portion 95u, which constitutes the upper side of the tube 95, is formed in a substantially cylindrical shape, and a ring-shaped fin 95f is formed on the outer peripheral surface at the upper end thereof.
The fitting recess 95m is coaxially formed at the lower end of the tube upper portion 95u. The tube top 95
The u and the lower portion 95d of the tube are formed as thin as possible while maintaining a predetermined strength by cold forging or the like.

The upper tube portion 95u is integrated with a first core 98 for forming an upper water jacket 87 of the cylinder head 80, as shown in FIG. Further, the tube lower portion 95d is integrated with the second core 99 for forming the lower water jacket 86 of the cylinder head 80. The upper tube 95u and the first
The method of integrating the core 98 and the tube lower portion 95d with the second core 99 is the same as in the case of the first embodiment.

Then, the second core 99 is inserted into the fitting recess 95m of the tube upper portion 95u integrated with the first core 98.
By inserting the fitting convex portion 95p of the tube lower portion 95d integrated with the first core 98 with respect to the second core 99, the first core 98 is held in a fixed positional relationship as shown in FIG. To be done.

Next, a method of manufacturing the cylinder head 80 will be described. First, the fitting recess 95 of the tube upper portion 95u
The fitting convex portion 95p of the tube lower portion 95d is fitted to m, and the first core 98 and the second core 99 are combined. Here, when applying the coating agent to the first core 98, the second core 99, etc., the edge of the lower end portion of the tube lower portion 95d forming the ceiling portion 82t of the combustion chamber 82 is expanded into a flange shape. Apply the coating agent especially thickly. The first core 98, the second core 99, etc. coated with the mold coating agent in this manner are set at predetermined positions of a mold (not shown). As in the case of the first embodiment, the intake passage core, the exhaust passage core and the oil jacket core are also set in the mold. Next, the mold is clamped, the molten metal is injected into the mold, and the cylinder head 80 is cast.

As described above, in the method of manufacturing the cylinder head 80 according to the present embodiment, the ceiling portion 82t of the combustion chamber 82 is formed.
From the lower part of the plug hole 85 to the lower part of the tube 95d
, And the central portion of the plug hole 85 is formed by casting and enclosing the tube upper portion 95u, and the tube upper portion 95u and the tube lower portion 95d are formed by forging or the like. Therefore, it is possible to easily improve the strength from the ceiling surface of the combustion chamber to the plug hole as compared with the conventional case where the ceiling surface of the combustion chamber and the plug hole are formed by casting. Furthermore, the wall thickness can be reduced while ensuring the strength from the ceiling surface of the combustion chamber to the plug hole. Therefore, the cooling effect in the combustion chamber and the plug hole can be improved. Since the tube upper part and the tube lower part are fitted together, the positioning of the first core and the second core becomes easy.

Further, since the edge of the lower end portion of the lower tube portion 95d forming the ceiling portion 82t of the combustion chamber 82, which is widened like a flange, is applied with a particularly thick coating agent, the casting base material and the casting base material after casting are applied. A gap is formed between the lower edge of the tube lower portion 95d and the edge by removing the coating agent. For this reason,
The thermal expansion of the lower tube portion 95d can be absorbed by the gap, and the thermal strain of each cylinder does not affect the adjacent cylinders.

Although the embodiments of the present invention have been described above, it should be noted that the embodiments of the present invention have the following technical matters in addition to the technical matters described in the claims. I'll do it. (1) In the cylinder head described in claim 2,
The tube is a forged cylinder head.

[0051]

According to the present invention, the required amount of cooling water can be made to flow in the vicinity of the combustion chamber, so that cooling around the combustion chamber can be promoted. Further, since the temperature inside the plug hole can be efficiently transmitted to the cooling water inside the water jacket, the cooling efficiency inside the plug hole is improved.

[Brief description of drawings]

FIG. 1A is a cross-sectional view in a width direction of a cylinder head according to a first embodiment of the present invention. Figure 1 (B)
[FIG. 2] is a BB arrow view of FIG.

FIG. 2 is a vertical cross-sectional view of a mold for manufacturing the cylinder head according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a core forming a water jacket of the cylinder head according to the first embodiment of the present invention.

FIG. 4 is an exploded cross-sectional view in the width direction of a core forming a water jacket of the cylinder head according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view in the width direction of a core forming a water jacket of the cylinder head according to the first embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of a mold for manufacturing a cylinder head according to a second embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of a mold for manufacturing a cylinder head according to a second embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of a tube used for manufacturing a cylinder head according to a third embodiment of the present invention.

FIG. 9 is a widthwise sectional view of a cylinder head according to a fourth embodiment of the present invention.

FIG. 10 is an exploded cross-sectional view in the width direction of a core forming a water jacket of a cylinder head according to a fourth embodiment of the present invention.

FIG. 11 is a cross-sectional view in the width direction of a core forming a water jacket of a cylinder head according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 cylinder head 2 combustion chamber 5 plug holes 6 Lower water jacket 7 Upper water jacket 15 tubes 18 1st core 19 Second core 75 tubes 75f fin 80 cylinder head 85 Plug hole 95u tube top 95d tube bottom

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F01P 3/02 F01P 3/02 G F02F 1/00 F02F 1/00 K 1/24 1/24 B H (72) Inventor Nishimura Akira Shoichi, Toyota City, Aichi Prefecture 1 Toyota Town, Ltd. (56) Reference JP-A-6-74043 (JP, A) JP-A-9-323151 (JP, A) JP-A-7-1003069 (JP , A) JP 11-141396 (JP, A) JP 7-266020 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02F 1/00-1/42 F01P 3/02 B22C 9/10 B22C 9/22 B22D 19/00 B22D 19/08

Claims (7)

(57) [Claims] 1. A cylinder head in which a water jacket is partitioned by a wall formed along a flow direction of cooling water into a portion for cooling around a combustion chamber and a portion for cooling other portions, the combustion head comprising: A plug hole communicating with the chamber is formed by casting a tube, and the tube is arranged so as to penetrate a water jacket that cools around the combustion chamber and a water jacket that cools other parts .
The wall thickness of the tube is the wall thickness of the cast-in part.
The thickness is the thickness of the part that penetrates the water jacket.
Cylinder head characterized by being set smaller than the law . 2. A step of manufacturing a tube for forming a plug hole communicating with a combustion chamber , setting the tube in a core mold, and blowing sand into the core mold.
For water jackets where the tube penetrates
While molding the first core of the
Tube with the tube integrated, and with the tip of the tube threaded
Having a receiving hole into which a step formed on the
A step of forming a second core for the jacket, and a step of forming the tip of the tube integrated with the first core into the second core.
Insert the step of the tube into the receiving hole of the child
In the fitted state, the tip end surface of the tube was brought into contact with a mold for molding a combustion chamber, and a casting pin was inserted into the tube from the first core side to press the tube .
A method of manufacturing a cylinder head , comprising the steps of: clamping in a state and casting . 3. A process of manufacturing a lower part of a tube that constitutes a lower part of a plug hole and a ceiling of a combustion chamber, and an upper part of a tube that constitutes a main part of the plug hole with a structure that can be fitted with the lower part of the tube. The upper part of the tube is integrated with the first core for the water jacket, and the lower part of the tube is integrated with the second core for the water jacket .
And a step of fitting the tube upper part and the tube lower part together,
The step of casting after setting the core and the second core in the mold
When manufacturing method of a cylinder head and having a. 4. The method of manufacturing a cylinder head according to claim 3, wherein after the step of integrating the lower part of the tube with the second core for the water jacket, the ceiling part of the combustion chamber in the lower part of the tube. step of applying a coating agent to the edge of the portion constituting the
A method of manufacturing a cylinder head, comprising: 5. The method of manufacturing a cylinder head according to claim 2, further comprising a step of cooling the tube during casting. 6. The method of manufacturing a cylinder head according to claim 2, further comprising a step of manufacturing a tube having fins formed in a portion in direct contact with the molten metal. A method for manufacturing a characteristic cylinder head. 7. The method according to any one of claims 2 to 6.
And a method of manufacturing a cylinder head, comprising: The wall thickness of the part to be cast in penetrates the water jacket
Chu smaller than the wall thickness of the
To a cylinder characterized by having a step of manufacturing
Method of manufacturing a pad.